Modtran: High Emissivity of 1 ppm CO2!

We see an effect of reducing OLR from 379 W/m2 to 373 W/m2 by adding 1 ppm CO2 to a carbon free atmosphere: Thus a warming effect of 6 W/m2 by adding 0.0001% CO2 to a dry atmosphere!!

We see warming effect of about 2 W/m2 by increasing CO2 to 600 ppm from present 400 ppm.

We see the effect of 6 W/m2 from the ditch in the spectrum (second graph from top) centered at the main resonance of CO2 at wave number 667, developing by adding just 1 ppm of CO2!

We thus see a very big effect from a very small cause, which directly triggers sound scientific skepticism: If one grain of salt can change the world, then either 10 grains will end it, or the effect quickly saturates maybe to no effect by adding more. Since the first option is absurd, only the second is thinkable and this is the IPCC logarithmic saturation effect: 6 W/m2 from 0 to 1 ppm, and 2 W/m2 from 400 to 600 ppm.

We compare with the absorption spectrum for 1000 m of 1 ppm CO2 computed by spectralcalc showing extreme sparsity of the absorption away from the narrow interval 667-669:

We thus find good reason to question the spectra produced by Modtran which serve as the main scientific evidence of a warming effect of CO2.

Thanks, but the reception is so hostile that I leave it to you. In any case I think there is substantial evidence showing that 0.039% CO2 cannot block radiation from the Earth surface in the whole band 600 - 800 as given by Modtran, only effectively in 667-669 say, and thus that the total emissivity is very small, smaller than 0.002, and vey little is gained by doubling the concentration. Radiative forcing of 3.7 W/m2 appears to be at least a factor 10 too big, and without those 3.7 W/m2, CO2 alarmism collapses to zero.

Here’s an analysis done with Spectralcalc which determines doubling of current CO2 levels could only raise surface temperature < 0.2 C, i.e. that climate sensitivity is exaggerated by more than a factor of 10.